// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2006-2010 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_BLOCK_H
#define EIGEN_BLOCK_H

namespace Eigen {

namespace internal {
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
struct traits<Block<XprType, BlockRows, BlockCols, InnerPanel>> : traits<XprType>
{
	typedef typename traits<XprType>::Scalar Scalar;
	typedef typename traits<XprType>::StorageKind StorageKind;
	typedef typename traits<XprType>::XprKind XprKind;
	typedef typename ref_selector<XprType>::type XprTypeNested;
	typedef typename remove_reference<XprTypeNested>::type _XprTypeNested;
	enum
	{
		MatrixRows = traits<XprType>::RowsAtCompileTime,
		MatrixCols = traits<XprType>::ColsAtCompileTime,
		RowsAtCompileTime = MatrixRows == 0 ? 0 : BlockRows,
		ColsAtCompileTime = MatrixCols == 0 ? 0 : BlockCols,
		MaxRowsAtCompileTime = BlockRows == 0				  ? 0
							   : RowsAtCompileTime != Dynamic ? int(RowsAtCompileTime)
															  : int(traits<XprType>::MaxRowsAtCompileTime),
		MaxColsAtCompileTime = BlockCols == 0				  ? 0
							   : ColsAtCompileTime != Dynamic ? int(ColsAtCompileTime)
															  : int(traits<XprType>::MaxColsAtCompileTime),

		XprTypeIsRowMajor = (int(traits<XprType>::Flags) & RowMajorBit) != 0,
		IsRowMajor = (MaxRowsAtCompileTime == 1 && MaxColsAtCompileTime != 1)	? 1
					 : (MaxColsAtCompileTime == 1 && MaxRowsAtCompileTime != 1) ? 0
																				: XprTypeIsRowMajor,
		HasSameStorageOrderAsXprType = (IsRowMajor == XprTypeIsRowMajor),
		InnerSize = IsRowMajor ? int(ColsAtCompileTime) : int(RowsAtCompileTime),
		InnerStrideAtCompileTime = HasSameStorageOrderAsXprType ? int(inner_stride_at_compile_time<XprType>::ret)
																: int(outer_stride_at_compile_time<XprType>::ret),
		OuterStrideAtCompileTime = HasSameStorageOrderAsXprType ? int(outer_stride_at_compile_time<XprType>::ret)
																: int(inner_stride_at_compile_time<XprType>::ret),

		// FIXME, this traits is rather specialized for dense object and it needs to be cleaned further
		FlagsLvalueBit = is_lvalue<XprType>::value ? LvalueBit : 0,
		FlagsRowMajorBit = IsRowMajor ? RowMajorBit : 0,
		Flags = (traits<XprType>::Flags & (DirectAccessBit | (InnerPanel ? CompressedAccessBit : 0))) | FlagsLvalueBit |
				FlagsRowMajorBit,
		// FIXME DirectAccessBit should not be handled by expressions
		//
		// Alignment is needed by MapBase's assertions
		// We can sefely set it to false here. Internal alignment errors will be detected by an eigen_internal_assert in
		// the respective evaluator
		Alignment = 0
	};
};

template<typename XprType,
		 int BlockRows = Dynamic,
		 int BlockCols = Dynamic,
		 bool InnerPanel = false,
		 bool HasDirectAccess = internal::has_direct_access<XprType>::ret>
class BlockImpl_dense;

} // end namespace internal

template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, typename StorageKind>
class BlockImpl;

/** \class Block
 * \ingroup Core_Module
 *
 * \brief Expression of a fixed-size or dynamic-size block
 *
 * \tparam XprType the type of the expression in which we are taking a block
 * \tparam BlockRows the number of rows of the block we are taking at compile time (optional)
 * \tparam BlockCols the number of columns of the block we are taking at compile time (optional)
 * \tparam InnerPanel is true, if the block maps to a set of rows of a row major matrix or
 *         to set of columns of a column major matrix (optional). The parameter allows to determine
 *         at compile time whether aligned access is possible on the block expression.
 *
 * This class represents an expression of either a fixed-size or dynamic-size block. It is the return
 * type of DenseBase::block(Index,Index,Index,Index) and DenseBase::block<int,int>(Index,Index) and
 * most of the time this is the only way it is used.
 *
 * However, if you want to directly maniputate block expressions,
 * for instance if you want to write a function returning such an expression, you
 * will need to use this class.
 *
 * Here is an example illustrating the dynamic case:
 * \include class_Block.cpp
 * Output: \verbinclude class_Block.out
 *
 * \note Even though this expression has dynamic size, in the case where \a XprType
 * has fixed size, this expression inherits a fixed maximal size which means that evaluating
 * it does not cause a dynamic memory allocation.
 *
 * Here is an example illustrating the fixed-size case:
 * \include class_FixedBlock.cpp
 * Output: \verbinclude class_FixedBlock.out
 *
 * \sa DenseBase::block(Index,Index,Index,Index), DenseBase::block(Index,Index), class VectorBlock
 */
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
class Block
	: public BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind>
{
	typedef BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, typename internal::traits<XprType>::StorageKind> Impl;

  public:
	// typedef typename Impl::Base Base;
	typedef Impl Base;
	EIGEN_GENERIC_PUBLIC_INTERFACE(Block)
	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Block)

	typedef typename internal::remove_all<XprType>::type NestedExpression;

	/** Column or Row constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Block(XprType& xpr, Index i)
		: Impl(xpr, i)
	{
		eigen_assert((i >= 0) && (((BlockRows == 1) && (BlockCols == XprType::ColsAtCompileTime) && i < xpr.rows()) ||
								  ((BlockRows == XprType::RowsAtCompileTime) && (BlockCols == 1) && i < xpr.cols())));
	}

	/** Fixed-size constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE Block(XprType& xpr, Index startRow, Index startCol)
		: Impl(xpr, startRow, startCol)
	{
		EIGEN_STATIC_ASSERT(RowsAtCompileTime != Dynamic && ColsAtCompileTime != Dynamic,
							THIS_METHOD_IS_ONLY_FOR_FIXED_SIZE)
		eigen_assert(startRow >= 0 && BlockRows >= 0 && startRow + BlockRows <= xpr.rows() && startCol >= 0 &&
					 BlockCols >= 0 && startCol + BlockCols <= xpr.cols());
	}

	/** Dynamic-size constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
	Block(XprType& xpr, Index startRow, Index startCol, Index blockRows, Index blockCols)
		: Impl(xpr, startRow, startCol, blockRows, blockCols)
	{
		eigen_assert((RowsAtCompileTime == Dynamic || RowsAtCompileTime == blockRows) &&
					 (ColsAtCompileTime == Dynamic || ColsAtCompileTime == blockCols));
		eigen_assert(startRow >= 0 && blockRows >= 0 && startRow <= xpr.rows() - blockRows && startCol >= 0 &&
					 blockCols >= 0 && startCol <= xpr.cols() - blockCols);
	}
};

// The generic default implementation for dense block simplu forward to the internal::BlockImpl_dense
// that must be specialized for direct and non-direct access...
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
class BlockImpl<XprType, BlockRows, BlockCols, InnerPanel, Dense>
	: public internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel>
{
	typedef internal::BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel> Impl;
	typedef typename XprType::StorageIndex StorageIndex;

  public:
	typedef Impl Base;
	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl)
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE BlockImpl(XprType& xpr, Index i)
		: Impl(xpr, i)
	{
	}
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE BlockImpl(XprType& xpr, Index startRow, Index startCol)
		: Impl(xpr, startRow, startCol)
	{
	}
	EIGEN_DEVICE_FUNC
	EIGEN_STRONG_INLINE BlockImpl(XprType& xpr, Index startRow, Index startCol, Index blockRows, Index blockCols)
		: Impl(xpr, startRow, startCol, blockRows, blockCols)
	{
	}
};

namespace internal {

/** \internal Internal implementation of dense Blocks in the general case. */
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel, bool HasDirectAccess>
class BlockImpl_dense : public internal::dense_xpr_base<Block<XprType, BlockRows, BlockCols, InnerPanel>>::type
{
	typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
	typedef typename internal::ref_selector<XprType>::non_const_type XprTypeNested;

  public:
	typedef typename internal::dense_xpr_base<BlockType>::type Base;
	EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)

	// class InnerIterator; // FIXME apparently never used

	/** Column or Row constructor
	 */
	EIGEN_DEVICE_FUNC
	inline BlockImpl_dense(XprType& xpr, Index i)
		: m_xpr(xpr)
		,
		// It is a row if and only if BlockRows==1 and BlockCols==XprType::ColsAtCompileTime,
		// and it is a column if and only if BlockRows==XprType::RowsAtCompileTime and BlockCols==1,
		// all other cases are invalid.
		// The case a 1x1 matrix seems ambiguous, but the result is the same anyway.
		m_startRow((BlockRows == 1) && (BlockCols == XprType::ColsAtCompileTime) ? i : 0)
		, m_startCol((BlockRows == XprType::RowsAtCompileTime) && (BlockCols == 1) ? i : 0)
		, m_blockRows(BlockRows == 1 ? 1 : xpr.rows())
		, m_blockCols(BlockCols == 1 ? 1 : xpr.cols())
	{
	}

	/** Fixed-size constructor
	 */
	EIGEN_DEVICE_FUNC
	inline BlockImpl_dense(XprType& xpr, Index startRow, Index startCol)
		: m_xpr(xpr)
		, m_startRow(startRow)
		, m_startCol(startCol)
		, m_blockRows(BlockRows)
		, m_blockCols(BlockCols)
	{
	}

	/** Dynamic-size constructor
	 */
	EIGEN_DEVICE_FUNC
	inline BlockImpl_dense(XprType& xpr, Index startRow, Index startCol, Index blockRows, Index blockCols)
		: m_xpr(xpr)
		, m_startRow(startRow)
		, m_startCol(startCol)
		, m_blockRows(blockRows)
		, m_blockCols(blockCols)
	{
	}

	EIGEN_DEVICE_FUNC inline Index rows() const { return m_blockRows.value(); }
	EIGEN_DEVICE_FUNC inline Index cols() const { return m_blockCols.value(); }

	EIGEN_DEVICE_FUNC
	inline Scalar& coeffRef(Index rowId, Index colId)
	{
		EIGEN_STATIC_ASSERT_LVALUE(XprType)
		return m_xpr.coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
	}

	EIGEN_DEVICE_FUNC
	inline const Scalar& coeffRef(Index rowId, Index colId) const
	{
		return m_xpr.derived().coeffRef(rowId + m_startRow.value(), colId + m_startCol.value());
	}

	EIGEN_DEVICE_FUNC
	EIGEN_STRONG_INLINE const CoeffReturnType coeff(Index rowId, Index colId) const
	{
		return m_xpr.coeff(rowId + m_startRow.value(), colId + m_startCol.value());
	}

	EIGEN_DEVICE_FUNC
	inline Scalar& coeffRef(Index index)
	{
		EIGEN_STATIC_ASSERT_LVALUE(XprType)
		return m_xpr.coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
							  m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
	}

	EIGEN_DEVICE_FUNC
	inline const Scalar& coeffRef(Index index) const
	{
		return m_xpr.coeffRef(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
							  m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
	}

	EIGEN_DEVICE_FUNC
	inline const CoeffReturnType coeff(Index index) const
	{
		return m_xpr.coeff(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
						   m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
	}

	template<int LoadMode>
	inline PacketScalar packet(Index rowId, Index colId) const
	{
		return m_xpr.template packet<Unaligned>(rowId + m_startRow.value(), colId + m_startCol.value());
	}

	template<int LoadMode>
	inline void writePacket(Index rowId, Index colId, const PacketScalar& val)
	{
		m_xpr.template writePacket<Unaligned>(rowId + m_startRow.value(), colId + m_startCol.value(), val);
	}

	template<int LoadMode>
	inline PacketScalar packet(Index index) const
	{
		return m_xpr.template packet<Unaligned>(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
												m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0));
	}

	template<int LoadMode>
	inline void writePacket(Index index, const PacketScalar& val)
	{
		m_xpr.template writePacket<Unaligned>(m_startRow.value() + (RowsAtCompileTime == 1 ? 0 : index),
											  m_startCol.value() + (RowsAtCompileTime == 1 ? index : 0),
											  val);
	}

#ifdef EIGEN_PARSED_BY_DOXYGEN
	/** \sa MapBase::data() */
	EIGEN_DEVICE_FUNC inline const Scalar* data() const;
	EIGEN_DEVICE_FUNC inline Index innerStride() const;
	EIGEN_DEVICE_FUNC inline Index outerStride() const;
#endif

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const typename internal::remove_all<XprTypeNested>::type& nestedExpression()
		const
	{
		return m_xpr;
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE XprType& nestedExpression() { return m_xpr; }

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR StorageIndex startRow() const EIGEN_NOEXCEPT
	{
		return m_startRow.value();
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR StorageIndex startCol() const EIGEN_NOEXCEPT
	{
		return m_startCol.value();
	}

  protected:
	XprTypeNested m_xpr;
	const internal::variable_if_dynamic<StorageIndex, (XprType::RowsAtCompileTime == 1 && BlockRows == 1) ? 0 : Dynamic>
		m_startRow;
	const internal::variable_if_dynamic<StorageIndex, (XprType::ColsAtCompileTime == 1 && BlockCols == 1) ? 0 : Dynamic>
		m_startCol;
	const internal::variable_if_dynamic<StorageIndex, RowsAtCompileTime> m_blockRows;
	const internal::variable_if_dynamic<StorageIndex, ColsAtCompileTime> m_blockCols;
};

/** \internal Internal implementation of dense Blocks in the direct access case.*/
template<typename XprType, int BlockRows, int BlockCols, bool InnerPanel>
class BlockImpl_dense<XprType, BlockRows, BlockCols, InnerPanel, true>
	: public MapBase<Block<XprType, BlockRows, BlockCols, InnerPanel>>
{
	typedef Block<XprType, BlockRows, BlockCols, InnerPanel> BlockType;
	typedef typename internal::ref_selector<XprType>::non_const_type XprTypeNested;
	enum
	{
		XprTypeIsRowMajor = (int(traits<XprType>::Flags) & RowMajorBit) != 0
	};

  public:
	typedef MapBase<BlockType> Base;
	EIGEN_DENSE_PUBLIC_INTERFACE(BlockType)
	EIGEN_INHERIT_ASSIGNMENT_OPERATORS(BlockImpl_dense)

	/** Column or Row constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE BlockImpl_dense(XprType& xpr, Index i)
		: Base(xpr.data() +
				   i * (((BlockRows == 1) && (BlockCols == XprType::ColsAtCompileTime) && (!XprTypeIsRowMajor)) ||
								((BlockRows == XprType::RowsAtCompileTime) && (BlockCols == 1) && (XprTypeIsRowMajor))
							? xpr.innerStride()
							: xpr.outerStride()),
			   BlockRows == 1 ? 1 : xpr.rows(),
			   BlockCols == 1 ? 1 : xpr.cols())
		, m_xpr(xpr)
		, m_startRow((BlockRows == 1) && (BlockCols == XprType::ColsAtCompileTime) ? i : 0)
		, m_startCol((BlockRows == XprType::RowsAtCompileTime) && (BlockCols == 1) ? i : 0)
	{
		init();
	}

	/** Fixed-size constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE BlockImpl_dense(XprType& xpr, Index startRow, Index startCol)
		: Base(xpr.data() + xpr.innerStride() * (XprTypeIsRowMajor ? startCol : startRow) +
			   xpr.outerStride() * (XprTypeIsRowMajor ? startRow : startCol))
		, m_xpr(xpr)
		, m_startRow(startRow)
		, m_startCol(startCol)
	{
		init();
	}

	/** Dynamic-size constructor
	 */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
	BlockImpl_dense(XprType& xpr, Index startRow, Index startCol, Index blockRows, Index blockCols)
		: Base(xpr.data() + xpr.innerStride() * (XprTypeIsRowMajor ? startCol : startRow) +
				   xpr.outerStride() * (XprTypeIsRowMajor ? startRow : startCol),
			   blockRows,
			   blockCols)
		, m_xpr(xpr)
		, m_startRow(startRow)
		, m_startCol(startCol)
	{
		init();
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const typename internal::remove_all<XprTypeNested>::type& nestedExpression()
		const EIGEN_NOEXCEPT
	{
		return m_xpr;
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE XprType& nestedExpression() { return m_xpr; }

	/** \sa MapBase::innerStride() */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index innerStride() const EIGEN_NOEXCEPT
	{
		return internal::traits<BlockType>::HasSameStorageOrderAsXprType ? m_xpr.innerStride() : m_xpr.outerStride();
	}

	/** \sa MapBase::outerStride() */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR Index outerStride() const EIGEN_NOEXCEPT
	{
		return internal::traits<BlockType>::HasSameStorageOrderAsXprType ? m_xpr.outerStride() : m_xpr.innerStride();
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR StorageIndex startRow() const EIGEN_NOEXCEPT
	{
		return m_startRow.value();
	}

	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE EIGEN_CONSTEXPR StorageIndex startCol() const EIGEN_NOEXCEPT
	{
		return m_startCol.value();
	}

#ifndef __SUNPRO_CC
	// FIXME sunstudio is not friendly with the above friend...
	// META-FIXME there is no 'friend' keyword around here. Is this obsolete?
  protected:
#endif

#ifndef EIGEN_PARSED_BY_DOXYGEN
	/** \internal used by allowAligned() */
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
	BlockImpl_dense(XprType& xpr, const Scalar* data, Index blockRows, Index blockCols)
		: Base(data, blockRows, blockCols)
		, m_xpr(xpr)
	{
		init();
	}
#endif

  protected:
	EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void init()
	{
		m_outerStride =
			internal::traits<BlockType>::HasSameStorageOrderAsXprType ? m_xpr.outerStride() : m_xpr.innerStride();
	}

	XprTypeNested m_xpr;
	const internal::variable_if_dynamic<StorageIndex, (XprType::RowsAtCompileTime == 1 && BlockRows == 1) ? 0 : Dynamic>
		m_startRow;
	const internal::variable_if_dynamic<StorageIndex, (XprType::ColsAtCompileTime == 1 && BlockCols == 1) ? 0 : Dynamic>
		m_startCol;
	Index m_outerStride;
};

} // end namespace internal

} // end namespace Eigen

#endif // EIGEN_BLOCK_H
